


Undersea Love Story

by afterosesuilen



Category: BanG Dream! (Anime), BanG Dream! Girl's Band Party! (Video Game)
Genre: Alternate Universe - Mermaids, Alternate Universe - Merpeople, Developing Relationship, Domestic Fluff, F/F, Female Friendship, Fluff, Friends to Lovers, Friendship, Friendship/Love, I also make an additional pet for Tomoe cause why not?, Interspecies, Interspecies Awkwardness, Interspecies Relationship(s), Interspecies Romance, Mermaids, Merpeople, Romance, Romantic Fluff, bandori rarepair, i had to do this, mermaid, mermaid au
Language: English
Status: In-Progress
Published: 2019-12-08
Updated: 2019-12-11
Packaged: 2021-02-26 07:09:03
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 2
Words: 2,733
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21719707
Author URL: https://archiveofourown.org/users/afterosesuilen/pseuds/afterosesuilen
Summary: Udagawa Tomoe is a mershark (shark-type mermaid), who loves to hunt animals under the sea. However, one day, while she was hunting, she got distracted by a beautiful singing voice from another mermaid, whose name is Minato Yukina. Although they are mermaids from different species and their first meeting was awkward, they really wanted to get close with each other...
Relationships: Background Minato Yukina/Mitake Ran, Background Yukiran, Minato Yukina/Udagawa Tomoe
Kudos: 4





	1. I Want to Get Along with You

In a vast ocean, there lived a mermaid that is good at hunting prey, named Udagawa Tomoe. Because she is a mershark (shark-type mermaid), all her life is used for hunting crustaceans, seashells, and small fish as her food.

One day, Tomoe was swimming under the sea, finding some small fish. She noticed a small fish swimming right past her.

“You’ll not getting away!”

Tomoe started to swim, chasing the small fish, but suddenly she got distracted by a very beautiful singing voice. Not long after that, the fish that she chased, fleed right in front of her.

“Oh damn it, this little fish has already run away. I need to know who made me distracted with this.”, she thought.

She immediately swam to the source of the singing voice. 5 minutes later, Tomoe found the source of the sound she heard earlier. She saw a girl with her long, silver hair who was singing, while she was hiding behind the seaweed.

“She looks so cute...”, she thought.

Suddenly, she turned back, knowing Tomoe’s appearance. She immediately hid herself again.

“Hm? Who looked at me earlier?”

The silver-haired mermaid then saw someone that she hasn’t ever seen before. She quickly swam into the seaweed where Tomoe was hiding, and afterwards, she grabbed something.

Tomoe felt like someone is pulling her body. She then turned back, looking at someone who grabbed her shark tail. It turned out that the person who grabbed her tail was her...

“Um, hey! Why are you grabbing my tail out of a sudden, huh?”

“Before you ask, I’m asking you this. Why are you following me?”, she asked back.

Tomoe then got nervous for a moment, and her face turned red. She felt that she was not confident enough to answer her question.

“Um...”

“Yeah, what is it?”

“I... I just wanted to interact with you more. Because of your amazing voice, I didn’t even got focused while I was hunting prey. I’m sorry for what I’ve done...”, said Tomoe, while hanging her head.

The silver-haired mermaid got surprised, her face turned red after hearing her answer. An awkward silence happened between both of them.

«««

Suddenly, she swam to Tomoe, going close to her. She was confused by her behavior, and she blushed afterwards.

“Eh? Why are you approaching me like that?”

“You look way different compared to the mermaid that I usually see. Are you a mershark?”

“Yeah.”

Tomoe nodded her head. But still, the mermaid gave her a judging look.

“Who are you?”

Tomoe panicked. Her face turned red again.

“Eeh? I... I...”

“Calm down, I just want to ask who you are.”, she tried to ensure Tomoe to keep calm.

“Um, My name is Udagawa Tomoe. Nice to meet you.”

“Minato Yukina. Actually, our introduction ends here, Udagawa-san. There’s something I had to do right now. See you later.”

Yukina then swam away, leaving Tomoe behind.

«««

The next morning, Tomoe woke up from her sleep, then swam out from her hiding place, which is a cave. As usual, she hunted her own prey by swimming in the areas that were close to the coral reef. The coral reef is located not far from her home, and there are a lot of fish and other animals.

3 small fish and some seashells have been caught successfully. Afterwards, she sat down on the rocks near the coral reef.

While she was eating her own catch, Yukina immediately swam close to her.

“Good morning, Udagawa-san.”

Tomoe was surprised, seeing her sitting next to her.

“Um, good morning too, Minato-san. By the way, what are you doing here?”

“Actually, I’m just swimming around, but because I meet you right here, I stop for a while to talk to you, Udagawa-san.”

Tomoe stopped for a while to find something, then she immediately offer her own catch to Yukina.

“Minato-san, do you want this? It’s delicious.”

Yukina refused the offer politely.

“I’ve already had breakfast this morning. Sorry, Udagawa-san.”

“It’s okay.”

★★★

The sun began to rise higher. Tomoe and Yukina were still sitting next to each other near the coral reef. Afterwards, Tomoe invited her to have fun together.

“Minato-san, do you want to swim together with me?”

Yukina nodded, as a sign of agreement.

“Yep. Coincidentally, I’m bored here.”

She held her hand. They immediately swam together, into a cave. The size of the cave is not too big.

After entering the cave, Yukina asked Tomoe something.

“Udagawa-san, this place is so dark. Why did we swim into this place?”

“Ah, it’s actually my home! I know it’s not as beautiful as the coral reef, but it’s still comfortable for me. Welcome!”

Tomoe gave her a surprise, which is a special present. The present was an ornamental pebble, engraved with a rose motif on top.

“Just take this thing, as a memory.”

Yukina received the gift. Not long after that, she thanked her, but also she asked Tomoe a question.

“Thank you, Udagawa-san. So, how come you are so skilled at making handicrafts like this?”

“Ahaha, that’s a long story. Aside from hunting, I love to discover some sunken things on the sea floor. However, I have ever got attacked by a shark, and it bit my left arm...”

“A shark? You mean, the fish, right?”

Tomoe nodded, and continued her story.

“...Fortunately, I was mildly injured. The wound has been recovered, so the scars aren’t visible anymore. But still, I’m too afraid to find more sunken stuff under the sea because of that incident. Then, I got another idea, which is making handicrafts. I started to collect some small pebbles, and as the engraving tool, I use shark teeth that have fallen out. It actually needs patience to make ornaments like this.”

“I see. Your handmade craft is so pretty...”

“Thanks for the compliment, Minato-san.”

«««

The sun shone at its peak and the ocean started to get warmer. Tomoe and Yukina went outside the cave. They swam into the coral reef. Tomoe was about to hunt again, but Yukina grabbed her hand...

“Udagawa-san, I’m asking you something.”

“Hm, what is it, Minato-san?”

“Mind if I braid your hair? Your hair is a bit messy, so I want to tidy it up. I don’t want it to get tangled while you were hunting.”

“Ah, about that... I don’t mind at all!”

“It’s ok, Udagawa-san. Just sit down in front of me.”

Tomoe sat down in front of her. Later on, Yukina started to caress her long red hair, using her own hands. She tied her hair into a single braid, without any additional accessory.

“There you go. You look beautiful.”

“T... thanks...”, Tomoe blushed.

A few moments later, Tomoe told Yukina an important thing before she went to hunt some prey.

“Please, don’t sing for a while, because I tend to get distracted easily. I want to hunt some food here, Minato-san.”

Yukina nodded her head.

“It’s fine. Have a great hunting.”

«««

“Minato-san, I’m back!”

Tomoe was exhausted from hunting. Yukina swam close to her.

“I can see that. Did you get something?”

Tomoe nodded. She took out something from a bag, made of woven plant fibers. The bag was found while she was swimming away, shortly before she caught her prey.

“Here, Minato-san! I got this!”, she exclaimed happily, holding out a small fish.

Other than the small fish she just caught, she also caught 3 other small fish, some seashells, 2 crabs, a pearl oyster, and a cuttlefish. But, the cuttlefish immediately sprayed some ink in front of Tomoe’s eyes, before it ran away.

“Ow!”

“Don’t worry, Udagawa-san. It’s just a spray of ink. It’s not that toxic, actually.”

Yukina waved her hand in front of Tomoe’s face, letting the ink spray fade away. Afterwards, Tomoe thanked her.

“Thanks, Minato-san! By the way, let’s eat lunch together!”

«««

After eating, Tomoe leaned herself on a stone formation that is located close to the coral reef. Yukina followed her.

Tomoe lay down, taking a nap. Yukina went close to her, fondling her braided hair while she was sleeping. She thought that Tomoe looked so cute when she was asleep.

Several moments later, Tomoe woke up from her sleep.

«««

The sun started to set. Tomoe and Yukina swam together into the cave, only to find themselves a sea lion pup. The sea lion pup cuddled Tomoe, making Yukina wanted to pat its head.

“Ah, who is this sea lion pup? It looks so cute!”

“It’s my pet, actually. Its name is Poci. She’s a female sea lion pup. However, she’s not always in this cave, because she only dives underwater just to find some food.”

“By the way, can I pat its head?”

“It’s ok, Minato-san! Poci doesn’t bite at all.”

Yukina then patted Poci’s head. She loved its soft fur.

Several moments later, the sea lion pup swam away, leaving both of them in the cave. It went back to the seashore.

«««

It’s night time. The sea temperature fell down. Tomoe and Yukina were still inside the cave, because there are a lot of nocturnal sea predators outside.

“Um... Udagawa-san, is it ok for me to stay here?”

“Yep, it is. For me, this place is safe enough to hide. Just stay with me from now on, Minato-san.”

Tomoe hugged her.

Afterwards, she yawned, as a sign that she was sleepy.

“You look sleepy, Udagawa-san. Maybe we can sleep together? I’m tired as well...”

“Yeah. It’s also cold here, looks like we need to cuddle together, Minato-san. I need warmth.”

Tomoe immediately let down her hair. Both of them lay down on the sea floor, closely to each other. Yukina leaned forward to Tomoe’s chest, cuddling her. Tomoe hugged her back and patted her head, making her face turned red.

A warm feeling appeared inside both of them. Tomoe’s finned ears twitched, and she leaned forward to gently kiss Yukina’s forehead, right before she fell asleep.

“Good night, Minato-san. Have a nice dream.”

“Good night, Udagawa-san.”

«««


	2. Lost Pet and A New Friend

**Summary for the Chapter:**

> Tomoe and Yukina started to hang out together more often. But, Tomoe's beloved pet, Poci, got lost... and they met a new friend.

The next morning, Yukina woke up from her sleep. She turned back and saw Tomoe, who was still asleep.

Yukina immediately came close to her and patted her head.

Not long after that, Tomoe woke up. She noticed someone patted her head, who is no other than Yukina herself.

“Looks like you finally wake up. Good morning, Udagawa-san.”

Tomoe quickly sat down on the sea floor, looking at her.

“Good morning, Minato-san. So, do you want to go out together?”

“Go out together? For what?”, Yukina asked.

“You know, searching for food, enjoying the view... or even find new things.”

“I see. Alright then, let’s go, Udagawa-san.”

«««

Tomoe and Yukina immediately swam out from the cave. All of a sudden, a sea lion pup came close to both of them. Tomoe quickly caught it. It was no other than Poci, Tomoe’s pet.

“Ahaha! Hello there, Poci!”, said Tomoe while hugging her own pet.

She then slowly stroke its fur, shortly before it swam away to find itself some food. Afterwards, Yukina asked her a question about her pet.

“Udagawa-san, how long have you kept Poci as a pet?”

“Poci has been with me since 4 months ago. Sadly, her biological mother died at that time, so she had to live alone. Because of this, I had to take care of her. If she haven’t got any food, usually I help her by hunting some small fish. Poci loves it.”

“I see. You really care about your pet, don’t you?”

Tomoe nodded, while laughing nervously.

“Well, yeah. By the way, I’m hungry. Let’s go find some food!”, Tomoe then grabbed Yukina’s hand.

“Alright. Let’s go, Udagawa-san.”

«««

Both of them immediately went to the coral reef, which was located near their home. In that place, there were a lot of small fish swimming around.

Tomoe immediately chased some shoals of small fish as fast as she can. Because she was a skilled hunter and also a talented tracker, her hunting this time brought up a major improvement. She caught 8 small fish, some seashells, and a crab.

Meanwhile, Yukina found some seaweed. Seaweed and some certain algae were part of her diet, so she had to find a lot of them.

After finding some food, Tomoe and Yukina sat down near the stone formation, which is located not far from the coral reef. They ate their own catch happily, until Tomoe felt something suspicious...

“Minato-san, it’s been long time we’re here, but I haven’t seen any signs of Poci.”

“Poci? Why you brought it up all of a sudden, Udagawa-san?”

“You see, I’m her owner, so I know when she usually came to me. But for this time, she hasn’t come to me since this morning... I feel worried.”

“Calm down, Udagawa-san. Don’t be panicked. I’m sure both of us can find her. Let’s go find Poci after eating, then.”

“Alright, Minato-san.”

«««

The sun rose higher. But, Tomoe and Yukina were still wandering around, finding Tomoe’s lost pet.

“Poci, where are you?”, Tomoe called for her. However, her call only left an echo under the sea.

“Have you searched for her inside the cave?”, Yukina asked.

“Yes, I have. But, I haven’t found her at all...”

Tomoe started to call for Poci once again. But, her call still ended up with no answer. She started to panic.

“Poci... where are you now?”

There was still no answer.

Tomoe sulked in despair, almost cried. Yukina came closer to comfort her.

“Udagawa-san. It’s okay. Please, don’t cry.”

Suddenly, someone went closer to both of them. She’s also a mershark, but from a different shark species. She noticed the crying Tomoe and Yukina, who was still comforting her. But, she thought Yukina was the one making her cry.

“Hey! What’s your problem?”, the mershark got angry at Yukina.

“Eh? Um... I just want to comfort her...”

On the other hand, Tomoe noticed something familiar near the mershark. It was no other than its pet, Poci. She quickly chased it, and caught it afterwards.

“Poci... I’m worried about you...”, said Tomoe, patting its head.

«««

Tomoe went back to Yukina. However, she saw her arguing at another mershark. She immediately patted the mershark’s right shoulder, shortly before she turned back.

“Tomoe, what are you-“

“Wait, these two know each other?”, Yukina thought.

“Please, don’t fight with her. She is my close friend.”

Both of them stopped arguing with each other.

“Why are both of you here? Is there something happened?”, the mershark asked them.

“So, here. I and Udagawa-san were wandering around, to find her lost pet sealion pup. We searched and searched for her, but no visible signs of her, and she cried afterwards. When we saw you, Udagawa-san noticed her pet near you, so yeah. I’m sorry about this misunderstanding.”

“I’m sorry as well. Anyway, what’s your name?”

“Minato Yukina. I’m Udagawa-san’s close friend.”

“Mitake Ran. I’m Tomoe’s childhood friend, so it’s not really surprising for you. About her pet... I actually saw it swimming past me, and it tends to play with my tail a lot. But, I was confused why it was there. I’m sorry for not realizing that.”

“Ahaha, don’t mind about it, Ran! You can be friends with Minato-san too!”, Tomoe exclaimed by patting Ran’s head.

Ran immediately got embarassed. Her face turned red.

“Fine. You really hang out with Minato-san, but know what... I won’t interact very often to her. I’m awkward as hell.”

“Ahaha! It’s ok, Ran! Don’t worry about it. Minato-san is a nice person.”

“Let’s be friends, Mitake-san.”, said Yukina, lending her hand.

Ran, still blushing, grabbed her hand.

“Um... yeah. From now on, we’re friends.”

«««

The sun was about to set. Poci has already swum away to the seashore. However, Ran felt her stomach growling. She then said farewell to Tomoe and Yukina, waving her hand before she swam away.

“Anyway, I gotta go. I want to hunt some food. See you later, Tomoe and Minato-san.”

Tomoe and Yukina waved back to her. Afterwards, they went back to Tomoe’s cave.

«««

It’s nighttime. Yukina felt really tired after helping Tomoe to find her lost pet, so she slept earlier than usual. Tomoe went close to her, patted her head, and hugged her. Yukina’s finned ears began to twitch while she was cuddling her.

Both of them were finally asleep.

Meanwhile, Ran was in front of her cave, swimming around to find prey for herself to eat. However, she was unable to sleep...

«««

**Notes for the Chapter:**

> 1\. I'll add some other Bandori characters, but all of them are mermaids. I won't give a big conflict because the genre in this fanfic are fluff, friendship and romance.  
> 2\. Ran is a mershark, and her species is a tiger shark!

**Author's Note:**

> Actually, I did this at the end of October, but the idea started to flow since yesterday. Mermaid AU's are quite fun and intriguing to do, however, there are not much lifestyle about normal mermaids that I found, especially how do they eat (they're mythical creatures, after all!)
> 
> Also, the Roselia song "Sanctuary" influenced me to make this. Mermaid Yukina's design will be heavily based from her 4* in that event. Mermaid Tomoe's design... Let me see. I want to use @sundoodle_EP (twitter)'s design, but, on the contrary I want to modify it, adding her some additional clothing as well.
> 
> Thanks to some people who help me adding headcanons, especially @goodbyesadplanet on tumblr and @brokendream27 on Instagram!


End file.
